In some of the lightest winds of the season so far, which made foiling a real challenge for the SailGP teams, Japan won both of Saturday's two fleet races to mount a remarkable comeback and qualify for the Final, where they were joined by Australia and Great Britain.
The breeze picked up slightly for the Final, but the 'wind-whisperer' Nathan Outteridge could not overcome rival Slingsby, the Season 1 champion, who celebrated a second successive event win with an on-boat champagne moment
The Brits, meanwhile, rounded out the podium after penalty drama in the Final forced the team to drop behind Japan, though Ainslie and his team were visibly aggrieved at the controversial decision.
Final results
1. Tom Slingsby, AUS, 10 points
2. Nathan Outteridge, JPN, 9
3. Ben Ainslie, GBR, 8
4. Jimmy Spithill, USA, 7
5. Peter Burling, NZL, 6
6. Nicolai Sehested, DEN, 5
7. Phil Robertson, Spain, 4
8. Billy Besson, FRA, 3
